US 11,856,216 B2
Signaling residual signs predicted in transform domain
Alexey Konstantinovich Filippov, Moscow (RU); and Vasily Alexeevich Rufitskiy, Moscow (RU)
Assigned to Huawei Technologies Co., Ltd., Shenzhen (CN)
Filed by Huawei Technologies Co., Ltd., Shenzhen (CN)
Filed on Aug. 14, 2020, as Appl. No. 16/994,076.
Application 16/994,076 is a continuation of application No. PCT/RU2018/000205, filed on Mar. 29, 2018.
Prior Publication US 2021/0014509 A1, Jan. 14, 2021
Int. Cl. H04N 19/176 (2014.01); H04N 19/48 (2014.01); H04N 19/13 (2014.01); H04N 19/14 (2014.01); H04N 19/159 (2014.01); H04N 19/18 (2014.01); H04N 19/463 (2014.01); H04N 19/593 (2014.01); H04N 19/91 (2014.01); H04N 19/174 (2014.01); H04N 19/61 (2014.01); H04N 19/645 (2014.01)
CPC H04N 19/48 (2014.11) [H04N 19/13 (2014.11); H04N 19/14 (2014.11); H04N 19/159 (2014.11); H04N 19/174 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/463 (2014.11); H04N 19/593 (2014.11); H04N 19/61 (2014.11); H04N 19/91 (2014.11); H04N 19/645 (2014.11)] 19 Claims
OG exemplary drawing
 
1. An apparatus for encoding an image block including processing circuitry configured to:
predict a sign for each of M non-zero transform coefficients obtained by transforming an image block signal with a plurality of transformations, M being an integer larger than 1 and smaller than a number of non-zero transform coefficients obtained by transforming the image block, wherein the sign prediction is based on a cost function calculated in a transform domain rather than a spatial domain;
wherein the cost function includes a sum of squared transformed differences between adjacent pixels neighboring a transformed image block and a prediction of the adjacent pixels calculated based on a prediction signal of the image block;
determine a sign prediction error for each of the M non-zero transform coefficients indicating whether or not the sign was correctly predicted;
select a context for entropy coding of each sign prediction error of each transform coefficient of the M non-zero transform coefficients according to the plurality of transformations; and
encode one sign prediction error of one transform coefficient of the M non-zero transform coefficients by applying entropy coding using corresponding selected context,
wherein fewer than all of the non-zero transform coefficients obtained by transforming the image block signal with the plurality of transformations are used for encoding the image block; and
wherein the cost function in the transform domain satisfies the following:

OG Complex Work Unit Math
wherein tn=Trans1D(Tn), qn=Trans1D(Qn), νn=Trans1D(Vn), and on=Trans1D(On),
wherein F is the cost function, Trans1D(·) is a one-dimensional orthogonal transform and Tn=[2Xn,−1−Xn,−2−Pn,0], Vm=[2Z−1,m−Z−2,m−P0,m], Qn=Rn,0 and Om=R0,m,
wherein P is prediction signal, X and Z are neighboring pixels, N and M are height and width of the block in which the signs are predicted, and R is a prediction error pixel, respectively.